code: def _make_efficientnet_backbone(effnet):
      pretrained = nn.Module()
  
      pretrained.layer1 = nn.Sequential(
          effnet.conv_stem, effnet.bn1, effnet.act1, *effnet.blocks[0:2]
      )
      pretrained.layer2 = nn.Sequential(*effnet.blocks[2:3])
      pretrained.layer3 = nn.Sequential(*effnet.blocks[3:5])
      pretrained.layer4 = nn.Sequential(*effnet.blocks[5:9])
  
      return pretrained
  
imports: import torch
  import torch.nn
  from .vit import _make_pretrained_vitb16_384, _make_pretrained_vitb_rn50_384, _make_pretrained_vitl16_384
label_desc: Use image node_id 4 for calling a global function with example usage: _make_efficientnet_backbone(effnet) and returns: pretrained